Calibration system and housing

• US 5,278,072 A
• Filed: 03/12/1992
• Issued: 01/11/1994
• Est. Priority Date: 04/26/1990
• Status: Expired due to Fees

• Current Assignee: Terumo Cardiovascular Systems Corporation (Terumo Corporation)
• Original Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Inventors: Maxwell, Thomas P., Wall, Roxanne E.
• Primary Examiner(s): ALEXANDER, LYLE
• Application Number:
  US07/849,753
• Time in Patent Office: 670 Days
• Field of Search: 436/8-11, 422/68.1, 422/81, 422/102, 422/103, 128/DIG. 12-13
• US Class Current: 436/8
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: B01F 25/4522 the components being pressed through porous bodies, e.g. flat plates, blocks or cylinders, which obstruct the whole diameter of the tube B01F25/45243 takes precedence
• CPC Class Codes: G01N 27/4163 checking the operation of, or calibrating, the measuring apparatus G01N27/3274, G01N27/4175 and G01N33/0006 take precedence
• CPC Class Codes: G01N 27/4165 for pH meters
• CPC Class Codes: Y10S 128/12 Pressure infusion
• CPC Class Codes: Y10S 128/13 Infusion monitoring
• CPC Class Codes: Y10T 436/10 Composition for standardization, calibration, simulation, stabilization, preparation or preservation; processes of use in preparation for chemical testing
• CPC Class Codes: Y10T 436/102499 Blood gas standard or control

Abstract

A calibration system comprising a sensor cassette including at least one sensor to be calibrated and a housing having a liquid passage including a chamber. The housing is coupled to the sensor cassette to place the liquid passage in fluid communication with the sensor cassette. The housing has a gas injection passage through which a gas can be injected into the liquid passage to mix with a calibration liquid in the housing. A gas vent vents the gas from the housing. Porous media is provided in the chamber. The gas and calibration liquid pass through the porous media, and the porous media assists in rapid mixing of the gas and the calibration liquid.

Claims

1. A calibration system comprising:

at least one sensor to be calibrated, said sensor being responsive to a characteristic of a gas;

a housing having a liquid passage including a chamber, said housing being coupled to the sensor to place the liquid passage in fluid communication with the sensor;

a sterile liquid in said liquid passage;

said housing having a gas injection passage through which a gas can be injected into the liquid passage to mix with the liquid;

means for venting the gas from the housing;

porous medium comprising an open cell foam positioned down stream from said gas injection passage and in said chamber so that the gas and liquid can pass through the open cell foam to assist in mixing of the gas and the liquid, said open cell foam having from about 3 to about 7 pores per inch and at least about 85 percent open volume; and

a barrier coated on said open cell foam to reduce any mass transfer between the open cell foam and the liquid and between the open cell foam and the gas.

2. A calibration system as defined in claim 1 wherein the open cell foam is a polyester-polyurethane foam.

3. A calibration system as defined in claim 1 wherein the barrier comprises polyxylylene.

4. A calibration system as defined in claim 1 wherein the open cell foam has about 96 percent open volume.

5. A calibration system as defined in claim 1 wherein the barrier comprises Parylene C.

6. A calibration system as defined in claim 1 wherein the housing includes a divider which divides the chamber into a sparging chamber section and a settling chamber section, said sparging chamber section being upstream from said settling chamber section, and wherein said porous medium is in the sparging chamber section.

7. A calibration system as defined in claim 6 wherein the porous media is in said sparging chamber section.

8. A calibration system as defined in claim 1 wherein the housing has a liquid inlet and a liquid outlet coupled to the sensor, said liquid passage includes an inlet section leading from the liquid inlet to a junction at the chamber, the gas injection passage leads to a location where the gas injection passage and the liquid passage meet for injecting gas into the inlet section of the liquid passage at said location and said outlet is located to receive liquid that has passed from the inlet section of the liquid passage through the porous media.

9. A calibration system as defined in claim 8 wherein the housing includes a divider which divides the chamber into a sparging chamber section and a settling chamber section, said sparging chamber section being upstream from said settling chamber section, said junction and said porous medium being in the sparging chamber section.

10. A calibration system as defined in claim 1 wherein at least a portion of the liquid passage is coated with a barrier which renders the liquid passage less permeable to the gas, a component of air, or both.

11. A calibration system as defined in claim 10 wherein the barrier coated on the portion of the liquid passage comprises polyxylylene.

12. A calibration system as defined in claim 10, wherein the barrier coated on the portion of the liquid passage comprises Parylene C.

13. A calibration system as defined in claim 1 wherein the venting means includes a gas vent on the housing leading from said chamber and the calibration system includes second porous media comprising a second open cell foam in the chamber intermediate the first mentioned open cell foam and the gas vent for reducing the likelihood of liquid passing through the gas vent.

14. A calibration system as defined in claim 7 wherein the second open cell foam has from about 3 to about 7 pores per inch and at least about 85 percent open volume.

15. A calibration system as defined in claim 13 further comprising a second barrier coated on the second open cell foam to reduce any mass transfer between the second open cell foam and the liquid and between the second open cell foam and the gas.

16. A calibration system as defined in claim 15 wherein the second barrier comprises polyxylylene.

17. A calibration system as defined in claim 15 wherein the second barrier comprises Parylene C.

18. A calibration system as defined in claim 15 wherein the least a portion of the liquid passage is coated with a barrier which renders the liquid passage less permeable to the gas, a component of air, or both.

19. A calibration system as defined in claim 18 wherein the barriers coated on both the first and second open cell foams comprise polyxylylene and wherein the barrier coated on the portion of the liquid passage comprises polyxylylene.

20. A calibration system as defined in claim 19 wherein said portion of the liquid passage is formed of a material comprising silicone.

21. A method of calibrating a sensor of the type having a flow-through passage, comprising the steps of:

pumping a sterile liquid through an endless path which includes the flow-through passage;

injecting a sterile gas into the path to create a partial pressure of the gas in the path;

mixing the gas with the sterile liquid in the endless path to control the partial pressure of at least a component of said gas in the sterile liquid;

said step of mixing including passing the gas and liquid through an open cell foam, the open cell foam having from about 3 to about 7 pores per inch and at least about 85 percent open volume, the open cell foam further comprising a barrier coated thereon to reduce any mass transfer between the open cell foam and the liquid and between the open cell foam and the gas;

venting at least some of the gas from the endless path; and

exposing the sensor to the sterile liquid having the controlled partial pressure of said component of said gas whereby the sensor can be calibrated.

22. A method as defined in claim 21 wherein the barrier comprises polyxylylene.

23. A method as defined in claim 21 wherein the barrier comprises Parylene C.

24. A method as defined in claim 21 wherein at least a portion of the endless path is coated with a barrier which renders the endless path less permeable to the gas, a component of air, or both.

25. A method as defined in claim 21 wherein said step of venting includes passing the gas through a second open cell foam subsequent to said step of mixing.

26. A method as defined in claim 25 wherein the second open cell foam is coated with a barrier to reduce any mass transfer between the second open cell and the liquid and between the second open cell foam and the gas.

27. A method as defined in claim 26 wherein the barrier coated on the second open cell foam comprises polyxylylene.

28. A method as defined in claim 26 wherein at least a portion of the endless path is coated with a barrier which renders the endless path less permeable to the gas, a component of air, or both.

29. A method as defined in claim 28 wherein the barriers coated on both open cell foams comprise polyxylylene and wherein the barrier coated on the portion of the endless path comprises polyxylylene.